The above link is a Chainlink oracle. It is hidden from the docs because the Chainlink team would like to chat with each protocol looking to use the feed. I believe @Romy is already in touch with them about this.
Alternatively, Abracadabra could just treat OETH as 1:1 with ETH, as Morpho has done with their OETH market, and Aave has done with their stETH market.